coz,
I'll pass on a tip I got from Hipower champ David Tubb. to remove stubborn copper fouling, first clean with your regular solvent to remove powder fouling. saturate a NEW bore brush with sweets 7.62. push it through the bore from the breach end. saturate it again at the muzzle. repeat 3 times at the muzzle, then push it through 10 times, saturate it again at the muzzle, and give it another 10 strokes. by this time, your cleaning rod will be covered with blue foam. let it sit for 10 min., then push 2 patches soaked in rubbing alcohol through the bore to nuetralize the sweets. A couple of dry patches, then a oiled patch, and it should be clean. you can also wash the bore brush in sweets so it doesn't dissolve. A bore brush won't hurt your barrel if you use a good coated rod, like a dewey, and a bore guide. this procedure is much, much faster than swabbing the bore with sweets and waiting for it to dissolve the copper.
Potshot